SIOUX CITY, IOWA — Sen. Elizabeth Warren, making her first official swing through this pivotal state, was forced to quickly confront an issue threatening to dog her throughout her presidential campaign: her claims of Native American ancestry.

An audience member, in the first question of the morning, asked Warren on Saturday why she underwent DNA testing last year and gave President Donald Trump “fodder to be a bully.”

Democratic presidential contenders are already locked in an important battle to showcase their viability, racing to build digital armies to power their campaigns.

Online support is set to play a pivotal role in the Democratic primaries, after small-dollar donors using ActBlue, the Democratic online fundraising platform, financed the Democratic House takeover — and, before that, Sen. Bernie Sanders’ underdog 2016 presidential campaign. Potential candidates have spent months building up grassroots digital supporters to fund their campaigns in 2019 and build relationships with voters before they get the chance to go to the polls in 2020.

Martin O’Malley’s announcement Thursday that he will not run for president may not have upended the 2020 presidential field. But by endorsing Beto O’Rourke at the same time he revealed his own departure from the race, O’Malley significantly advanced the case for the former Texas congressman in the Iowa crucible that could determine O’Rourke’s fate if he chooses to run.

Despite O’Malley’s weak performance in the Iowa caucuses in 2016 — he dropped out of the race on caucus night after receiving less than 1 percent of the vote — the former Maryland governor has spent years cultivating relationships with Democratic donors and activists in the first-in-the-nation caucus state. Even after the 2016 campaign, he spent months appearing in the state, traveling there for fundraisers and to help down-ticket Democrats in the midterm elections.

But one of the most important contests of the 2020 Democratic nominating process kicked off Wednesday night not at a county fair or diner, but inside MSNBC’s New York City studios, where Elizabeth Warren sat down with Rachel Maddow, the host of cable news’ recently crowned No. 1 show.

Dianne Feinstein’s California colleague Kamala Harris may run for president. But Feinstein already has her preferred candidate in mind: Joe Biden.

The Democratic senator, fresh off reelection to a fifth term, told a pair of reporters on Thursday morning that the former vice president and Delaware senator is the ideal choice to run against President Donald Trump. This despite the fact that more than a half-dozen Senate Democrats, including Harris, are considering running for president in 2020.

President Donald Trump again sought to wash his hands of responsibility for the partial government shutdown on Thursday, dismissing it as a ploy by Democrats to take the presidency in 2020.

"The Shutdown is only because of the 2020 Presidential Election. The Democrats know they can’t win based on all of the achievements of 'Trump,' so they are going all out on the desperately needed Wall and Border Security — and Presidential Harassment. For them, strictly politics!" Trump wrote on Twitter.

Former Maryland governor and Democratic presidential candidate Martin O’Malley shot down speculation that he would run for president again in 2020, instead saying he hoped Texas Rep. Beto O’Rourke would throw his hat in the ring.

The former longshot candidate laid out his reasons for endorsing O’Rourke in an op-ed in the Des Moines Register published Thursday, calling his failed Senate campaign “a disciplined and principled campaign that also managed to be raw, authentic, and real” and promoting O’Rourke, a former Democratic congressman from El Paso, Texas, as part of a “new generation” of leaders that can unify and heal the country.

Sen. Bernie Sanders apologized late Wednesday to female staffers who have said they endured sexual harassment and gender disparity while working on his 2016 presidential campaign, while also saying he was previously unaware of such allegations.

“I certainly apologize to any woman who felt that she was not treated appropriately, and of course if I run, we will do better next time,” Sanders said in an interview with CNN’s Anderson Cooper.

Bernie Sanders’ surprise performance against Hillary Clinton in 2016 was fueled by his dominance in a slate of states that voted by caucus, a format that allowed the Vermont senator to capitalize on his smaller but more fervent base of supporters.

Republican National Committee Chairwoman Ronna McDaniel connected with President Donald Trump by phone on Tuesday evening with some alarming news: Mitt Romney, her uncle, was about to publish an op-ed savaging him.

McDaniel, who had gotten a heads-up about the missive directly from Romney, was frustrated and knew she wanted to push back forcefully. That evening, she wrote a tweet defending the president. The next morning, as Romney’s op-ed took hold of the news cycle, McDaniel, Trump’s handpicked party chairwoman, sent out an even more strongly worded tweet scolding her uncle.

Sen. Elizabeth Warren announced the hiring of four high-level staffers in Iowa with deep caucus experience – including snagging Sen. Bernie Sanders’ former caucus director for the early presidential state.

Warren’s team announced the hires on Wednesday, just as the Massachusetts Democrat is scheduled to make her first round of Iowa stops this weekend. On Monday, Warren announced an exploratory presidential bid, becoming the first major Democratic contender to do so.

Sen. Elizabeth Warren will visit four cities in Iowa this weekend, her presidential exploratory committee said Tuesday, her first trip to the early caucus state since launching her 2020 exploratory committee on Monday.

The Massachusetts Democrat is scheduled to make stops in Council Bluffs, Sioux City, Storm Lake and Des Moines, according to her exploratory committee. Although Monday's committee announcement marked Warren's first concrete step toward a 2020 bid, the senator has been active in Iowa for weeks, speaking with candidates, elected officials, labor leaders and other Democratic stakeholders throughout the state.

President Donald Trump expressed excitement Monday at the prospect of running for president next year against Sen. Elizabeth Warren but told a Fox News interviewer that “you would have to ask her psychiatrist” if the Massachusetts Democrat believes she can beat him.

Earlier Monday, Warren (D-Mass.) announced she would launch an exploratory presidential committee, making her the highest-profile entrant in what is expected to be a crowded 2020 Democratic primary field. Trump, who has regularly targeted Warren for criticism and ridicule, salivated at the possibility that she might win the Democratic nomination.

The anti-Elizabeth Warren narrative was written before the Massachusetts senator even announced she was exploring a presidential run.

She’s too divisive and too liberal, Washington Democrats have complained privately. Her DNA rollout was a disaster — and quite possibly a White House deal-breaker. She’s already falling in the polls, and — perhaps most stinging — shares too many of the attributes that sank Hillary Clinton.

The Massachusetts Democrat and former Harvard Law professor filed papers Monday creating an exploratory presidential committee, becoming the first major potential 2020 contender to do so in what’s anticipated to be a sprawling Democratic field.

More than two dozen women and men who worked on Bernie Sanders’ 2016 presidential campaign are seeking a meeting with the senator and his top political advisers to “discuss the issue of sexual violence and harassment on the 2016 campaign, for the purpose of planning to mitigate the issue in the upcoming presidential cycle,” according to a copy of letter obtained by POLITICO.

“In recent weeks there has been an ongoing conversation on social media, in texts, and in person, about the untenable and dangerous dynamic that developed during our campaign,” they wrote.

“Democrats should not give an inch,” former Virginia Gov. Terry McAuliffe said Sunday when asked about the resolution of the partial government shutdown.

Referring to President Donald Trump as the “angry, emotional, unstable man sitting in the White House,” McAuliffe told CNN’s Dana Bash on “State of the Union” that Trump and his fellow Republicans are fully to blame for the shutdown — and that everybody knows the border wall at the crux of the shutdown dispute won’t be built.

In 2016, Sen. Mike Lee made a last-ditch attempt at the Republican National Convention to derail Donald Trump from winning his party’s presidential nomination — shouting on the floor until the convention chair walked off the stage. Two-and-a-half years later, he’s ready to endorse Trump’s reelection campaign.

“Look, I had some concerns and I expressed those,” Lee said in an interview. “I’ve been pleased with the number of things he’s done, and he’s been very helpful to me on criminal justice reform. … I’ve talked to him a lot and talking to him helps me develop a relationship with him.”